The various components of golf club design are generally well-known. These typically include a golf club head attached to a shaft and a grip. Depending on the type of club desired (i.e., an iron-, metalwood-, or driver-type club), specific subcomponents of the club head include face, heel, toe, sole, and, for a driver- or metalwood-type club, a crown, all of which can be tailored to directly impact the performance of the club. By varying the design specifications, therefore, manufacturers can tailor a golf club towards many specific performance characteristics.
Among the considerations in club head design are loft, lie, face angle, horizontal face bulge, vertical face roll, center of gravity (“c.g.”), moment of inertia (“MOI”), and material selection. The interior design of the club head may include a hosel or shaft attachment means or adjustability, perimeter weights, and/or fillers. Because golf club heads have repeated impacts with golf balls, they must also be strong enough to retain structural integrity.
Players generally seek a metalwood and/or driver that delivers maximum distance and accuracy when the ball is struck on the “sweet spot.” The sweet spot is the area of the club head that provides the maximum ball speed off the clubface while retaining the low golf ball spin required for maximum distance. Most current club heads are designed to have the sweet spot at the center (horizontally from face to toe, and vertically from sole to crown) of the face of the club. Additionally, the c.g. and bulge and roll are generally centrally positioned in line with the sweet spot.
One un-utilized anomaly of drivers and metalwoods, however, is that the sweet spot, while generally located in the center of the club face, is not located at the area of the club face that has the highest club head speed. Because the toe end of the club face is a greater distance from both the golfer (and, therefore, travels on a wider arc as the golf swings the club) and from the axis of the shaft (also traveling a wider arc as the club head rotates), it has a higher club head speed than the center of the club face, and an even greater difference in club head speed than the heel end of the club face. Even a small increase in club head speed is not unsubstantial when translated to yards of travel. A 1-mph increase in club head speed (at maximum COR) results in a 1.5-mph increase in ball speed. Given that for every mph increase in ball speed a gain of 2 yards in ball travel is noticed, this 1.5-mph increase results in 3 yards gained, without changing any other properties.
Because virtually all golf club manufacturers produce clubs with centrally-located sweet spots (and c.g.), the advantage of the higher club head speed near the toe of the club face has been ignored. There remains a need, therefore, for club head constructions that allow manufacturers to produce more forgiving drivers or metalwood clubs for mid-to-high handicap players while taking advantage of positioning the sweet spot and c.g. towards the toe of the club head which can lead to increased distance.